According to statistics, by far, there are approximately 0.17 billion patients suffered from diabetes over the world, about 90% of which are the patients suffered from type II (i.e. non-insulin-dependent) diabetes. Currently, the diabetes drugs used in clinical application are primarily the drugs of metformins, sulfonylureas and insulins. In recent years, the antidiabetic drugs on the market are also thiazolidinediones and α-glucosidase inhibitors and the like. These drugs possess good therapeutic effects, but lead to safety issues when being administered in long-term, e.g. liver toxicity and weight increase and the like.
Dipeptidyl peptidase IV, DPP-IV is able to degrade glucagon-like peptide-1 (GLP-1) effectively and rapidly, GLP-1 is one of the most effective stimulants in the production and secretion of insulin. Therefore, inhibitor DPP-IV is able to enhance the effect of the endogenous GLP-1, and thereby increase the insulin levels in the blood (See CN200480017355.6). Recently, medical research has already confirmed that DPP-IV inhibitor is a novel antidiabetic drug (Deacon C. F., Hoist J. J., Dipeptidyl Peptidase IV Inhibitors: A Promising New Therapeutic Approach for the Management of Type 2 Diabetes. The International Journal of Biochemistry & Cell Biology, 2006, 38 (5-6): 831-844). The clinical results showed that such drugs had good effect of reducing sugar without typical adverse reactions such as weight increase and hypoglycemia caused by other diabetes drugs.